1. Field of the Invention
The present invention relates to a speaker and more particularly, to a suspension member for speaker, which utilizes multiple transversely arched annular convex surface portions to achieve a sufficient support to the cone, while preventing distortion of sound.
2. Description of the Related Art
A speaker is a converter means that converts electric signal into sound signal for output. Many electronic devices such as broadcasting system, stereo system, TV, computer, multimedia system, etc., commonly use speakers for output of sound. A speaker has a voice coil mounted within a magnet. When the voice coil is electrically connected to produce a magnetic induction, the voice coil is caused to move forwards and backwards along an axis when an electric current is supplied thereto, thereby producing a sound wave at a predetermined frequency. Different speakers use different voice coils to produce sound waves at different frequencies. Due to the fast development of technology and change of living style, people are critical to the requirement of the sound quality of a speaker. In addition to the requirement of increasing sound volume, sound quality is an important factor that must be taken into account when selecting a speaker.
A speaker includes some parts, i.e., an outer basket, a suspension member, a cone, and an inner exciter. Every part has a great concern with the performance of the speaker. FIGS. 7, 8 and 8A show the outer appearance of a suspension member and a speaker. As illustrated, the speaker comprises a basket A, an exciter B mounted in a center area within a holding space Al of the basket A, a cone C suspending around the exciter B, and a suspension member D fastened to a rim of the basket A and connected to a periphery of the cone C to hold the cone C around the exciter B. During operations of the exciter B, the cone C is moved up and down to produce sound. The maximum amount of displacement of the cone C is the stroke of the speaker. The suspension member D is designed to establish a support power to the cone C. The suspension member D is made of an elastic material, having a curved surface portion Dl to fit the motion of the cone C.
However, because the suspension member D has one single curved surface portion D1 extending around the border area, the supporting power of the suspension member D to the cone C is limited. If the stroke of the speaker surpassed the supporting power provided by the suspension member D to the cone C, a distortion of sound will occur. In this case, the user cannot enjoy a high quality of sound. If to extend the size of the curved surface portion D1, the supporting power will be relatively reduced, and the stroke of the cone C will be relatively increased, resulting in distortion of sound. Further, changing the size of the curved surface portion D1 of the suspension member D must relatively change the structure of the basket A and the cone C, thereby increasing the manufacturing cost.
Besides, a loudspeaker system of the prior art is disclosed in which the transducer comprises a chassis, a diaphragm located within the chassis, an electromagnetic actuator, which has a first actuator part connected to the back part of the diaphragm and a second actuator part connected to the chassis to cooperate with the first actuator part via an air gap, a telescoping arrangement coupled between the chassis and the diaphragm, and suspension means for flexibly suspending the diaphragm from the chassis via the telescoping arrangement. This design greatly increases the area of the suspension, thereby lowering the supporting power to support the cone and relatively increasing the stroke of the cone. In order to fit the extended size of the suspension, the basket and the cone must be specially designed.
Further, a transducer suspension of the prior art is disclosed. According to this design, the suspension member is comprised of a dense non-cellular silicone rubber material such that the suspension member operates reliably over an extremely wide temperature range, having an outer edge portion attached to the main body of the transducer, an inner edge portion attached to a diaphragm, and a resilient region extending between the outer and inner edge portion. According to this design, the resilient region is insufficient to support the movement of the cone, and a distortion of sound may be produced during the operation of the speaker system.
Further, a suspension design of the prior art is disclosed. According to this design, the suspension member is a resilient member having multiple curved surface portions. Because the suspension member is formed integral with the cone, the suspension member will oscillate with the cone during the operation of the speaker system, thereby affecting the sound quality of the cone. Further, the stroke of the cone gives an impact to the suspension member, causing the suspension member unable to effectively support the motion of the cone.
Therefore, it is desirable to provide a suspension member that eliminates the aforesaid drawbacks.